Date: Mon, 23 Sep 2013 15:33:19 -0700 From: Sean Bruno <sean_bruno@yahoo.com> To: Kirk McKusick <mckusick@mckusick.com> Cc: freebsd-fs <freebsd-fs@freebsd.org> Subject: Re: kern/vfs_mount.c vfs_donmount() checks of MFSNAMELEN Message-ID: <1379975599.1593.10.camel@localhost> In-Reply-To: <201309231802.r8NI2KmF083133@chez.mckusick.com> References: <201309231802.r8NI2KmF083133@chez.mckusick.com>
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On Mon, 2013-09-23 at 11:02 -0700, Kirk McKusick wrote:
> > So, I'm confused by this check:
> >=20
> > if (fstypelen >=3D MFSNAMELEN - 1 || fspathlen >=3D MNAMELEN -
> 1) {
> > error =3D ENAMETOOLONG;
> > goto bail;
> > }
> >=20
> > MFSNAMELEN is 16, why do we check against >=3D MFSNAMELEN - 1? Why
> dont
> > we check against (> MFSNAMELEN - 1) or (>=3D MFSNAMELEN)? Is a 14
> > character fstypelen with a "\0" at the end considered too long?
> >=20
> > Sean
> >=20
> > p.s. e.g. mount -t fuse.glusterfs ...
>=20
> I agree with you. It should either be (> MFSNAMELEN - 1) or (>=3D
> MFSNAMELEN).
>=20
> Kirk McKusick=20
Not sure if we should adjust MNAMELEN or not too while we're at it, I
need to do a bit more of a code audit before thunking that one.
Propsed patch to set fstyplen check:
Index: sys/kern/vfs_mount.c
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
--- sys/kern/vfs_mount.c (revision 255831)
+++ sys/kern/vfs_mount.c (working copy)
@@ -656,7 +656,7 @@
* variables will fit in our mp buffers, including the
* terminating NUL.
*/
- if (fstypelen >=3D MFSNAMELEN - 1 || fspathlen >=3D MNAMELEN - 1) {
+ if (fstypelen >=3D MFSNAMELEN || fspathlen >=3D MNAMELEN - 1) {
error =3D ENAMETOOLONG;
goto bail;
}
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